Ruby
Ruby | |
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![]() Naitural ruby crystals frae Winza, Tanzanie | |
General | |
Category | Mineralvariety |
Formula (repeatin unit) | aluminium oxidewichromium,Al2O3:Cr |
Creestal seestem | Trigonal(Hexagonal Scalenohedral), symbol (−3 2/m),space groupR3c |
Identification | |
Colour | Reid, mey be brounish, purplish, or pinkish |
Creestal habit | Varies wi locality. Terminated tabular hexagonal prisms. |
Cleavage | Na true cleavage |
Fractur | Uneven or conchoidal |
Mohs scalehaurdness | 9.0 |
Skinkle | Vitreous |
Streak | white |
Diaphaneity | transparent |
Speceefic gravity | 4.0 |
Refractive index | nω=1.768–1.772 nε=1.760–1.763 |
Birefringence | 0.008 |
Pleochroism | Orangey reid, purplish reid |
Ultravioletfluorescence | reid unner longwave |
Meltin pynt | 2044 °C |
Solubility | none |
Major varieties | |
Sapphire | Ony color except shades o reid |
Corundum | various colors |
Emery | Granular |
Arubyis a pink tae bluid-reid colouredgemstane,a variety o themineralcorundum(aluminium oxide). The reid colour is caused mainly bi the presence o the elementchromium.Its name comes fraeruber,Laitinfor reid. Ither varieties o gem-quality corundum are criedsapphires.The ruby is considered ane o the fowerprecious stanes,thegither wi thesapphire,theemerald,an thediamond.[1]
Prices o rubies are primarily determined bi colour. The brichtest an maist valuable "reid" cried bluid-red, commands a lairge premium ower ither rubies o seemilar quality. Efter colour follaes clarity: seemilar tae diamonds, a clear stane will command a premium, but a ruby wioot ony needle-likrutileinclusions mey indicate that the stane haes been treatit. Cut ancarat(wicht) are an aa an important factor in determinin the price.
References
[eedit|eedit soorce]- ↑Precious Stones,Max Bauer, p. 2